Pre JDK 1.4 compatibility (even when compiled on JDK 1.4 or later)

git-svn-id: https://svn.apache.org/repos/asf/ant/core/trunk@473792 13f79535-47bb-0310-9956-ffa450edef68

src/main/org/apache/tools/ant/taskdefs/Replace.java

@@ -271,7 +271,8 @@ public class Replace extends MatchingTask {
          */
         void flush() {
             replace();
-            outputBuffer.append(inputBuffer);
+            // Avoid runtime problem on pre 1.4 when compiling post 1.4
+            outputBuffer.append(inputBuffer.toString());
             inputBuffer.delete(0, inputBuffer.length());
         }